1. Field of the Invention
The present invention relates to an IPTV service provision, and more particularly, to a method and apparatus for controlling a channel for providing an IPTV service.
2. Discussion of the Related Art
With the recent development of communication and Internet technologies, a TPS (Triple Play Service) for simultaneously transmitting broadcasting data, telephonic data, and other data via a signal subscriber line has been introduced in the market. There is the increasing demand for the TPS since the TPS provides users with a variety of services in a package through the single subscriber line. Thus, the number of service provision enterprises is also increased rapidly.
A typical example of the TPS is an IPTV (Internet Protocol Television) service. The IPTV service provides users with broadcasting services over a conventional Internet network. In comparison to the conventional broadcasting services, for example, cable-broadcasting service, satellite-broadcasting service, terrestrial-broadcasting service, the IPTV service can use network resources more effectively.
As shown in FIG. 1A, the conventional broadcasting services transmit data of all channels to the users without regard to user's request, thereby causing a waste of broadband. However, as shown in FIG. 1B, according as an IP multicast technology is introduced to the IPTV service, the IPTV service transmits only channel requested by the user. Thus, the IPTV service can overcome the bandwidth problem caused by the insufficient subscriber line.
However, the IPTV service has such a structure that the corresponding channel is transmitted by the user's request. When the user requests the new channel, a delay time (hereinafter, referred to as a channel zapping time) occurs until the new channel selected by the user is outputted to the user terminal.
In order to reduce the channel zapping time, the various channels have to be always provided to the users without regard to the user's request, as shown in the conventional broadcasting services. In this case, a bit rate of each channel has to be maintained at a low level due to limitation of bandwidth, thereby causing an avoidable degradation in quality of received video data.
If the bit rate of each channel is raised to enhance the quality of received video data, the quality may be improved. However, due to the limitation of resources, the number of channels with types to be provided to the users is decreased so that the channel zapping time is increased.
Accordingly, there is an increasing requirement for a method which is capable of maintaining the short channel zapping time and the high video quality in a trade-off relation.